Oxidation of glutamic acid by the splanchnic bed in humans.
Battezzati, A., D. J. Brillon, and D. E. Matthews.
Departments of Medicine and of Surgery, Cornell University Medical
College, New York, NY 10021
APStracts 2:0070E, 1995.
ob]1,2-13C2]Glutamate and [ring-2H5]phenylalanine were infused for 7
hours into postabsorptive healthy subjects on two occasions. The
tracer infusion was by intravenous route for 3.5 h and by nasogastric
route for 3.5-h. The order of tracer infusion routes was switched
between the two occasions. From the plasma tracer enrichment
measurements at plateau during the intravenous and enteral infusion
periods, we determined that 33+/-3% of the enterally delivered
phenylalanine and 96+/-1% of the glutamate were removed on the first
pass by the splanchnic bed. 78+/-3% of the enterally delivered
glutamate 13C tracer was recovered as exhaled CO2, compared to 79+/
-2% of the iv infused tracer. The fraction of the enterally delivered
tracer that was sequestered specifically on the first pass by the
splanchnic bed was 75+/-2%. These results verify the previously
reported large uptake of [15N]glutamate by the splanchnic bed
(Matthews et al., Am. J. Physiol. 264: E848, 1993) and demonstrate
that the uptake of tracer is not due to an artifactual loss of the
15N tracer by reversible transamination, but due to glutamate uptake
for oxidation.
Received 12 January 1995; accepted in final form 31 March 1995.
APS Manuscript Number E011-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.